[GIS] Measuring distance between points in ArcMap – what coordinate system to use

arcmapcoordinatesMeasurementswgs84

This is a basic -newbie – question. I have some handwritten data points taken off a GPS – so I am assuming they are in WGS 84, and I want to load them in ArcMap 9.3, via excel, and measure the distance between them (they are transects). I would like to know how best to maintain accuracy, and what format the data the coordinates should be when I load them into ArcMap.

The coordinates look like: 39. 51 550, 148.16 841 but the way they have been written they could be 39. 51 .50, 148.16.841 or 39 51.550, 148 16.841. Do these look like WGS 84 coordinates and what is the best way to input them into excel? Do I have to set or reset the projection in ArcMap before I take the measurements?

As you can see I am not confident with the basics of the coordinate system and projection system so any help and tips would be appreciated.

Best Answer

The coordinates look like degrees decimal-minutes. You'll need to convert them to decimal degrees to import them as WGS84. Do this in excel and then add the table to ArcGIS as an Excel table. Then create an XY Event layer from the coordinates. Finally, convert this to a geodatabase feature class of shapefile.

If you want to measure the distances between points on a one by one basis, your best bet is to use the measure tool's geodesic option. See this topic for more detail: http://webhelp.esri.com/arcgiSDEsktop/9.3/index.cfm?TopicName=Measuring_distances_and_areas

Craig

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